Organic light emitting display device and method of manufacturing the same

ABSTRACT

Provided is a method of manufacturing an organic light emitting display device in which a laser beam is used. The method includes forming an organic light emitting unit on a substrate; forming a sealing unit that seals the organic light emitting unit; forming an protective film which is opaque on the sealing unit to protect the organic light emitting unit or the sealing unit by blocking the transmission of the laser beam; forming an optical pattern on the opaque protective film using the laser beam; and forming a transparent film from the opaque protective film by oxidizing the opaque protective film.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of Korean Patent Application No.10-2008-0054301, filed on Jun. 10, 2008, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic light emitting displaydevice and a method of manufacturing the same, and more particularly, toan organic light emitting display device that can prevent the organiclight emitting display device from being damaged by a laser which isused in the manufacturing process and a method of manufacturing thesame.

2. Description of the Related Art

Generally, flat panel display (FPD) devices can be classified intodevices that use inorganic material and devices that use organicmaterial. Devices that use inorganic material include plasma displaypanels (PDPs) that use photo luminescence (PL) and field emissiondisplays (FEDs) that use cathode luminescence (CL). Devices that use anorganic material include liquid crystal crystals (LCDs) and organiclight emitting diodes (OLED).

An OLED includes a pixel electrode and a facing electrode which faceeach other, and a light emitting layer interposed between the pixelelectrode and the facing electrode. The OLED is easily damaged bymaterials such as moisture or oxygen if they penetrate into the device,and thus, the OLED is sealed so that the impurities cannot penetrate.

Organic light emitting display device that uses the OLED element has aresponse speed higher than that of a liquid crystal display (LCD) whichis currently widely in commercial use, and thus, they can realizesuperior motion images, are emissive, have wide viewing angles, and havehigh brightness. Thus, organic light emitting display device that usesthe OLED element is expected to be the next generation of displaydevice.

SUMMARY OF THE INVENTION

To address the above and/or other problems, the present inventionprovides an organic light emitting display device in which an organiclight emitting unit or a sealing unit is protected from a laser used inthe process of manufacturing the organic light emitting display deviceand a method of manufacturing the same.

According to an aspect of the present invention, there is provided amethod of manufacturing an organic light emitting display device, inwhich a laser beam is used, the method comprising: forming an organiclight emitting unit on a substrate; forming a sealing unit that sealsthe organic light emitting unit; forming an protective film which isopaque on the sealing unit to protect the organic light emitting unit orthe sealing unit by preventing the transmission of the laser beamtherethrough; forming an optical pattern on the opaque protective filmusing the laser beam; and forming a transparent film from the opaqueprotective film by oxidizing the opaque protective film.

The protective film may be formed of a material that is opaque in anoxygen-free atmosphere and may be transparent after reacting withoxygen.

The protective film may be formed of a metal that is opaque in anoxygen-free atmosphere and is transparent after reacting with oxygen.

The protective film may be formed of Calcium or Lithium.

The forming of the protective film may comprise forming the protectivefilm in an oxygen-free atmosphere.

The forming of the protective film may comprise forming the protectivefilm using a deposition method.

The forming of the optical pattern may comprise forming the opticalpattern in an oxygen-free atmosphere.

The forming of the optical pattern may comprise forming the opticalpattern using a laser induced thermal imaging (LITI).

The optical pattern may be a color filter or light absorption layer.

The forming of the transparent film may comprise exposing the protectivefilm to oxygen or to air.

The sealing unit may comprise at least two layers.

The sealing unit may have a structure in which an organic layer and aninorganic layer are alternately stacked.

According to another aspect of the present invention, there is providedan organic light emitting display device comprising: a substrate; anorganic light emitting unit formed on the substrate; a sealing unitsealing the organic light emitting unit; a protective film formed on thesealing unit; and an optical pattern formed on the protective film usinga laser beam, wherein the protective film protects the organic lightemitting unit or the sealing unit by preventing transmission of thelaser beam therethrough.

The protective film may be formed of a material that is opaque in anoxygen-free atmosphere and is transparent after reacting with oxygen.

The protective film may be formed of a metal that is opaque in anoxygen-free atmosphere and is transparent after reacting with oxygen.

The protective film may be formed of Calcium or Lithium.

The protective film may reflect the laser beam in an oxygen-freeatmosphere and be transparent after reacting with oxygen.

The optical pattern may be a color filter or a light absorption layer inan oxygen-free atmosphere.

The sealing unit may comprise at least two layers.

The sealing unit may have a structure in which an organic layer and aninorganic layer are alternately stacked.

According to the organic light emitting display device and method ofmanufacturing the same as described above, a sealing unit or an organiclight emitting unit can be protected from a laser used in the process ofmanufacturing the organic light emitting display device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIGS. 1 through 5 are cross-sectional views illustrating a method ofmanufacturing an organic light emitting display device according to anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. The invention may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the concept of the invention to those skilled in the art. In thedrawings, the thicknesses of layers and regions are exaggerated forclarity. Like reference numerals in the drawings denote like elements.

FIGS. 1 through 5 are cross-sectional views illustrating a method ofmanufacturing an organic light emitting display device according to anembodiment of the present invention.

Referring to FIG. 1, an organic light emitting unit 102 is formed on asubstrate 101.

The substrate 101 can be formed of a material such as transparent glass,plastic sheet, or silicon. The substrate 101 may be flexible ornon-flexible and may be transparent or non-transparent. Also, thesubstrate 101 can be a metal plate.

The organic light emitting unit 102 can be formed on the substrate 101.The organic light emitting unit 102 includes a plurality of lightemitting devices (OLEDs). Each of the OLEDs includes a pixel electrode,a facing electrode facing the pixel electrode, and an intermediate layerthat includes at least one light emitting layer interposed between thepixel electrode and a facing electrode. The pixel electrode can be atransparent electrode or a reflection electrode. If the pixel electrodeis a transparent electrode, the pixel electrode can be formed of ITO,IZO, ZnO, or In₂O₃, and if the pixel electrode is a reflectionelectrode, the pixel electrode can include a reflection film formed ofAg, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound of these materialsand a film formed of ITO, IZO, ZnO, or In₂O₃ on the reflection film. Thefacing electrode can also be a transparent electrode and a reflectionelectrode. If the facing electrode is a transparent electrode, thefacing electrode can include a film deposited using Li, Ca, LiF/Ca,LiF/Al, Al, Mg or a compound of these materials to face the intermediatelayer interposed between the pixel electrode and the facing electrode,and an auxiliary electrode or a bus electrode line formed of thematerial used to form the transparent electrode, such as ITO, IZO, ZnO,or In₂O₃ on the film. If the facing electrode is a reflection electrode,the facing electrode can be formed of Li, Ca, LiF/Ca, LiF/Al, Al, Mg, ora compound of these materials. The intermediate layer interposed betweenthe pixel electrode and the facing electrode can be formed of a smallmolecular weight organic material or a polymer organic material. If theintermediate layer is formed of a small molecular weight organicmaterial, the intermediate layer can be formed by stacking a holeinjection Layer (HIL), a hole transport layer (HTL), an emission layer(EML), an electron transport layer (ETL), or an electron injection layer(EIL) in a single structure or a composite structure, and can be formedof various materials such as copper phthalocyanine (CuPc),N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), ortris-8-hydroxyquinoline aluminum (Alq3). The intermediate layer formedof a small molecular weight organic material can be formed using avacuum evaporation method. If the intermediate layer is formed of apolymer organic material, the intermediate layer can have a structure inwhich an HTL and an EML are included, and the HTL can be formed of apolymer organic material such as poly-(2,4)-ethylene-dihydroxy thiophene(PEDOT), and the EML can be formed of a polymer organic material such asa poly-phenylenevinylene (PPV) group, or a polyfluorene group.

Next, referring to FIG. 2, a sealing unit 103 covering the organic lightemitting unit 102 is formed. The OLED of the organic light emitting unit102 can be easily degraded by a material such as moisture or oxygen.Thus, since the sealing unit 103 covers the organic light emitting unit102, penetration of moisture or oxygen into the organic light emittingunit 102 can be prevented, thereby preventing degradation of the OLED.

The sealing unit 103 can include at least two layers, that is, can havea structure in which an organic layer 103 a and an inorganic layer 103 bare alternately stacked. If the sealing unit 103 is formed using onlythe organic layer 103 a or only the inorganic layer 103 b, moisture oroxygen can penetrate from the outside through minute paths formed in theprotective film. Therefore, the sealing unit 103 can be formed toinclude multiple thin film layers using a structure in whichorganic-inorganic composite layers (the organic layer 103 a and theinorganic layer 103 b) are alternately deposited. If theorganic-inorganic composite layers are used, the organic layer 103 a canbe formed of an acryl group material and the inorganic layer 103 b canbe formed of a material such as aluminium oxide.

Referring to FIG. 3, a protective film 104 a is formed on the sealingunit 103. The protective film 104 a is formed of a material that isopaque in an oxygen-free atmosphere and is transparent when it isoxidized by reacting with oxygen. Thus, the protective film 104 a formedin an oxygen-free atmosphere is opaque. An oxygen-free atmosphere cancomprise an atmosphere completely devoid of oxygen or an atmospherehaving insufficient quantities of oxygen to oxidize the protective film.Since the protective film 104 a which is opaque is formed on the sealingunit 103 in an oxygen-free atmosphere, the opaque protective film 104 ablocks the transmission of a laser beam in a process in which a laserbeam is used. In this manner, the protective film 104 a protects theorganic light emitting unit 102 and the sealing unit 103 from the laserbeam, which will be described later. The protective film 104 a forprotecting the organic light emitting unit 102 and the sealing unit 103can be formed to cover the sealing unit 103.

The protective film 104 a can be formed of a material that is opaque inan oxygen-free atmosphere and is transparent when the material reactswith oxygen. In particular, the protective film 104 a can be formed of ametal that is opaque in an oxygen-free atmosphere and is transparentafter it is oxidized. Such metal includes Ca and Li. Thus, the opaqueprotective film 104 a can be formed by depositing Ca or Li on thesealing unit 103 in an oxygen-free atmosphere. After the protective film104 a is formed, the opaque state of the protective film 104 a ismaintained by maintaining the oxygen-free atmosphere.

Referring to FIG. 4, optical patterns 105 and 106 are formed on theprotective film 104 a. The optical patterns 105 and 106 can be formed onthe protective film 104 a using a laser. The optical patterns 105 and106 can be, for example, a color filter 105 or a light absorption layer106. The optical patterns 105 and 106 such as the color filter 105 orthe light absorption layer 106 can be formed using a laser inducedthermal imaging method.

The laser induced thermal imaging (LITI) requires at least a laserradiating device, an acceptor substrate, and a donor film. The donorfilm includes a base film, a light-to-heat conversion layer, and atransfer layer. In the LITI, after laminating the donor film onto theentire acceptor substrate in a state that the transfer layer is disposedto face the acceptor substrate, a laser beam is irradiated onto the basefilm. The laser beam radiated onto the base film is absorbed by thelight-to-heat conversion layer and is converted to heat energy, and thetransfer layer is transferred to the acceptor substrate due to the heatenergy. As a result, a transfer layer pattern is formed on the acceptorsubstrate.

If the color filter 105 is formed using LITI, the substrate 101 on whichthe organic light emitting unit 102, the sealing unit 103, and theprotective film 104 a are stacked performs as the acceptor substrate,and a material for forming the color filter 105 is the transfer layer ofthe donor film.

The formation of the color filter 105 using the LITI can be achieved bytransferring the color filter 105 onto the opaque protective film 104 aby irradiating a laser beam towards a pixel region of the organic lightemitting unit 102 after the color filter 105 is located in the pixelregion of the organic light emitting unit 102. In this case, the opaqueprotective film 104 a prevents the laser beam from being transmitted tothe sealing unit 103 or the OLED of the organic light emitting unit 102,which are formed under the opaque protective film 104 a, and thus,damage to the sealing unit 103 or the OLED element can be prevented.

The light absorption layer 106 can be a black matrix (BM). The lightabsorption layer 106 is formed in a non-light emitting region of theorganic light emitting unit 102, and can increase contrast and colorpurity of pixels by blocking light generated from light emitting regionsof the organic light emitting unit 102. The light absorption layer 106can also be formed using the laser induced thermal imaging method. Ifthe light absorption layer 106 is formed using the laser induced thermalimaging method, after the light absorption layer 106 is located on anon-light emitting region of the organic light emitting unit 102, alaser beam is irradiated towards the organic light emitting unit 102 sothat the light absorption layer 106 can be transferred onto the opaqueprotective film 104 a. The light absorption layer 106, unlike the colorfilter 105, is formed on the protective film 104 a corresponding to thenon-light emitting region and is not formed on the light emitting regionof the organic light emitting unit 102. However, since the laser beam isirradiated towards the organic light emitting unit 102, the OLED whichis in the light emitting region of the organic light emitting unit 102can be damaged. Since the protective film 104 a according to the presentinvention blocks the transmission of a laser beam, the protective film104 a can also protect the sealing unit 103 or the OLED of the organiclight emitting unit 102 from the laser beam in a process of forming thelight absorption layer 106 using the laser beam.

Next, referring to FIG. 5, a transparent film 104 b is formed byoxidizing the protective film 104 a. The transparent film 104 b isformed by exposing the protective film 104 a to an oxygen atmosphere orto air with sufficient oxygen to oxidize the protective film 104 a. Theprotective film 104 a is opaque in an oxygen-free atmosphere, and istransparent when it reacts with oxygen, and thus, if the protective film104 a is exposed to an oxygen atmosphere or to air, it is oxidized byreaction with oxygen, and thus the opaque protective film 104 a isconverted into the transparent film 104 b. If the protective film 104 ais formed of a metal that is opaque in an oxygen-free atmosphere and istransparent after reacting with oxygen, the transparent film 104 b is ametal oxide film. In particular, if the protective film 104 a is formedof a metal such as Ca or Li, the transparent film 104 b is CaO or LiO.Since the transparent film 104 b is transparent, a top emission typeorganic light emitting display device can be realized.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A method of manufacturing an organic light emitting display device,in which a laser beam is used, the method comprising: forming an organiclight emitting unit on a substrate; forming a sealing unit that sealsthe organic light emitting unit; forming an protective film which isopaque on the sealing unit to protect the organic light emitting unit orthe sealing unit by preventing transmission of the laser beamtherethrough; forming an optical pattern on the opaque protective filmusing the laser beam; and forming a transparent film from the opaqueprotective film by oxidizing the opaque protective film.
 2. The methodof claim 1, wherein the protective film is formed of a material that isopaque in an oxygen-free atmosphere and is transparent after reactingwith oxygen.
 3. The method of claim 2, wherein the protective film isformed of a metal that is opaque in an oxygen-free atmosphere and istransparent after reacting with oxygen.
 4. The method of claim 3,wherein the protective film is formed of Calcium or Lithium.
 5. Themethod of claim 1, wherein the forming of the protective film comprisesforming the protective film in an oxygen-free atmosphere.
 6. The methodof claim 5, wherein the forming of the protective film comprises formingthe protective film using a deposition method.
 7. The method of claim 5,wherein the forming of the optical pattern comprises forming the opticalpattern in an oxygen-free atmosphere.
 8. The method of claim 1, whereinthe forming of the optical pattern comprises forming the optical patternusing a laser induced thermal imaging (LITI).
 9. The method of claim 1,wherein the optical pattern is a color filter or a light absorptionlayer.
 10. The method of claim 1, wherein the forming of the transparentfilm comprises exposing the protective film to oxygen or to air.
 11. Themethod of claim 1, wherein the sealing unit comprises at least twolayers.
 12. The method of claim 11, wherein the sealing unit has astructure in which an organic layer and an inorganic layer arealternately stacked.
 13. An organic light emitting display devicecomprising: a substrate; an organic light emitting unit formed on thesubstrate; a sealing unit sealing the organic light emitting unit; aprotective film formed on the sealing unit; and an optical patternformed on the protective film using a laser beam, wherein the protectivefilm protects the organic light emitting unit or the sealing unit bypreventing transmission of the laser beam therethrough.
 14. The deviceof claim 13, wherein the protective film is formed of a material that isopaque in an oxygen-free atmosphere and is transparent after reactingwith oxygen.
 15. The device of claim 14, wherein the protective film isformed of a metal that is opaque in an oxygen-free atmosphere and istransparent after reacting with oxygen.
 16. The device of claim 15,wherein the protective film is formed of Calcium or Lithium.
 17. Thedevice of claim 13, wherein the protective film reflects the laser beamin an oxygen-free atmosphere and is transparent after reacting withoxygen.
 18. The device of claim 13, wherein the optical pattern is acolor filter or a light absorption layer in an oxygen-free atmosphere.19. The device of claim 13, wherein the sealing unit comprises at leasttwo layers.
 20. The device of claim 19, wherein the sealing unit has astructure in which an organic layer and an inorganic layer arealternately stacked.